Below you will find the instructions for installing the Apex Forward Set Sear and trigger.
You can download the PDF here:
The installation video is also available on Youtube at the following link:
Apex FSS Install
What you are looking at is our new forward set sear and trigger kit. I wanted to share some technical information about the parts and their interaction. First and most importantly the kit will provide a substantially shorter overall trigger travel than the stock M&P or our DCAEK.
The take up and over travel limits are defined by the trigger body. I wanted to ensure that no stresses were placed on the trigger bar/trigger connecting pin or trigger safety pin. I have seen several of both walk out on factory stock triggers and do not want this to occur in my design. The trigger uses the factory trigger bar and connecting pin from the original pistol that the kit is being integrated in to. We recommend that the pin be inserted into the trigger body from the left side, using a drop of oil on the hole to prevent binding or galling. We should have the install video up by the time you receive this package. The Aluminum trigger and safety lever are hard anodized black, so the hard durable shell is about .002″ in depth rather than the .0005″ depth of standard color anodizing. It should provide excellent service life.
The striker block plunger has been redesigned. Because we moved the trigger break point forward, we needed to ensure the striker block plunger cleared the channel as soon as possible. A domed or rounded factory striker block plunger or our current USB will most likely result in failures to fire and damage to both plunger and striker.
The sear has greater mechanical leverage than any of the sears currently manufactured (factory MIM, Pro sear, Tactical sear as well as our standard hard sear). The combination of springs should yield the following results:
• Factory TRS and sear spring- 3.0 lbs
• Competition spring kit- 2 lbs (or less)
• Springs included in kit- 4.0-4.25 lbs
The included sear spring is substantially stronger and has six coils. Due to the extremely short trigger travel, we STRONGLY recommend that you use a sear block with the current factory production .125” diameter sear spring/plunger, or have your sear block milled to accept the latest version.
Also included in the kit is a lighter weight RAM spring. Because the trigger break and trigger/sear reset point are closer together, the system can be more sensitive to sear flutter. Our standard weight RAM spring can increase the chances of the trigger bar popping back under the sear cam if the trigger loop is excessively worn.
We’re also now including a trigger bar pivot pin, pre installed into your trigger. When you remove the pin from the factory trigger, set the factory pin aside along with the trigger and use the FSS and the pre installed pin to attach the trigger bar.
Final notes: We left the trigger face square to encourage the shooter to articulate the trigger straight to the rear. A random group of test shooters in classes and in competition seemed to like the feel. We are also pursuing making a plastic version with rounded contours.
This is an evolutionary process so please let us know what you think.